This invention relates to a method for guiding a driver of a road vehicle along a route, the method comprising the steps of:
planning the route between a current position and a destination, the route comprising a number of road-elements, PA1 receiving and decoding a traffic message and therefrom deriving the actual travel condition of a particular road-element to which the message is directed, PA1 evaluating whether replanning the route is required, which evaluation comprises detecting whether the actual travel condition indicates a problem relating to one of the road-elements on the route to the destination and if this is the case then deciding to replan the route, and PA1 in the case of a positive decision, replanning the route between the current position and the destination. PA1 a planning module for planning the route between a current position and a destination, the route comprising a number of road-elements, PA1 a receiver for receiving and decoding a traffic message and therefrom deriving an actual travel condition of a particular road-element to which the message is directed, PA1 an evaluation module for evaluating whether replanning the route is required, which evaluation module is arranged to detect whether the actual travel condition indicates a problem relating to one of the road-elements on the route to the destination and if this is the case then to decide to replan the route. PA1 the method includes maintaining a list of travel conditions from received messages directed to road-elements in a relevance region, and PA1 in case the particular road-element is off the route the evaluation comprises detecting whether the actual travel condition indicates an improvement and if this is the case then deciding to replan the route. PA1 that the system is arranged to maintain a list of travel conditions from received messages directed to road-elements in a relevance region, and PA1 that the evaluation module is arranged to detect in case the particular road-element is off the route whether the actual travel condition indicates an improvement and if this is the case then to decide to replan the route. The navigation system according to the invention evaluates messages for road-elements off the route and in a certain relevance region, and compares the derived actual travel condition for such a road-element with a previously received travel condition, if any, for that road-element. If the comparison indicates that the travel condition for that road-element has improved, then the navigation system decides that replanning the route between the current position and the destination is required. The advantage is that a better route from the current position to the destination may now be found, because of the improved condition of a road-element that was not included in the originally planned route.
The invention further relates to a navigation system for guiding a driver of a road vehicle along a route, the system comprising:
Such a method and system are known from the European Patent EP 0 519 934 B1. The known system has means to plan a first route between a current position of the vehicle and a desired destination and has a receiver for receiving and evaluating traffic information. This first route is stored in a memory in the system and the system guides the driver of the vehicle along this route to the destination. When the system receives traffic information, it is determined to what particular road-element the traffic information is concerned. If the particular road-element is part of the first route in the memory, then a second route is planned between the current position and the destination whereby the second route does not comprise that particular road-element. The second route is also stored in the memory in the system and a comparison is made between the two routes. If the travel time for the second route is shorter than the total travel time for the first route, including the additional delay known from the traffic information, then the second route is used as the new route for guiding the driver to the desired destination.